[Heterologous expression of H2O-forming NADH oxidase in Torulopsis glabrata significantly enhance the pyruvate productivity of the host].
OBJECTIVE
The aim of this manuscript was to illuminate the effect of NADH oxidation pathway on the glycolytic rate and the pyruvate productivity.


METHODS
The noxE gene encoding a water-forming NADH oxidase from Lactococcus lactis, was expressed in a pyruvate producing Torulopsis glabrata CCTCC M202019. A mutant strain T. glabrata-PDnoxE, with specific NADH oxidase activity of 34.8 U/mg protein, was obtained.


RESULTS
During batch fermentation with 100 g/L glucose in the medium, the dry cell weight, the glucose consumption rate and pyruvate production rate were 168%, 44.9% and 12% higher than that of the parent strain, respectively. Only 2.5 g/L residual glucose was detected in the fermentation broth after 36 h culture, then 50 g/L glucose was supplemented to the culture broth and the concentration of pyruvate increased to 67.2 g/L. As the result of NADH oxidase overexpression, the intracellular NADH, NAD+ and ATP concentrations of the mutant and the parent strain were determined, the NADH and ATP content decreased 18.1% and 15.8% respectively, while the NAD+ concentration increased 11.1%.


CONCLUSIONS
The increasing of intracellular NAD+ concentration can efficiently enhance the rate of glucose consumption and the pyruvate production.
Dong
Zhiyao
Z
Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China. duke1983@163.com
Li
Xiufen
X
Liu
Liming
L
Du
Guocheng
G
Chen
Jian
J
D041221:Candida glabrata / Q000235:genetics* / Q000378:metabolism; D004274:DNA, Recombinant / Q000235:genetics; D004734:Energy Metabolism; D005285:Fermentation; D015870:Gene Expression; D006019:Glycolysis; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D019289:Pyruvic Acid / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
D004274:DNA, Recombinant; D009097:Multienzyme Complexes; D014867:Water; D009243:NAD; D019289:Pyruvic Acid; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D010100:Oxygen